Printers

• The criteria that you may want to consider when choosing a suitable printer include speed, print resolution, the quality of colour reproduction, paper handling, and the cost of consumables.
• Print resolution is measured in dots per inch (dpi), and a resolution of at least 300 dpi is needed for photo-quality images.
• Most printers will handle sheets of A4 paper, but some users need smaller or larger printouts. Some situations require specialist paper.
• Impact printers produce characters by striking the paper. They were once commonplace and useful for printing on multipart stationery (where the sheets are carbonated to produce two or more copies). Impact printers are noisy, and it is quite rare to find them in today's office environments. Faster, cheaper printers make it easy to produce multiple copies by selecting more than one copy, or by photocopying an original.
• Inkjet printers


  Non-impact printers that use liquid ink to produce black-and-white or colour prints
• Inkjet printers


  • Can cost anything from tens to hundreds of pounds depending on factors such as speed, quality, and paper handling capability
  • High-end inkjet printers can often handle specialist paper and print at very high resolutions
  • Liquid ink produces richer colours, making this type of printer the most suitable for printing photo-quality images
• Printer ink


  Often cited as being one of the most expensive commodities in the world, with small cartridges being the most expensive
• Inkjet printers


  • Usually the printer of choice in the home because of their low upfront cost
  • Preferred by photographers and for print studios because of their superior colour production and paper handling capabilities
• Laser printers


  Frequently used in the workplace
• Laser printers


  • Print a whole page at a time
  • Usually faster than inkjet printers
  • High-specification laser printers can produce 200 pages per minute
• Toner


  Powdered ink used in laser printers (instead of liquid ink)
• Toner cartridges


  • Quite large
  • Colour printers have four separate toner cartridges
  • Colour printers can be bulky and take up a lot of room
• Powdered ink


  • Cheaper than liquid ink
  • Lasts longer
• Laser printer consumables


  • Drum needs to be replaced from time to time
  • Must be factored into the overall cost of ownership
• Comparison sites often quote a cost per page to allow disparate printers to be compared
• Laser-printed output


  • Generally very good for text
  • Not so good for photo-quality images as it is difficult to produce deep, rich colours
• Plotters


  A plotter is a device that uses one or more pens to draw an image. Pens are lifted or applied to the paper as required, to produce a very precise drawing. Plotters are often large devices that can handle very wide paper, sometimes on a drum to allow repeated layers to be printed.

  Plotters are commonplace in engineering and architectural practices.
• 3D printers


  3D printing technology has developed rapidly over recent years, and costs have fallen to the point where many schools have them for use in art and product design. The printers work by interpreting a set of instructions that model an object in 3D space. Filament, usually in the form of plastic-based resin, is extruded at heat and applied to precise dimensions and location. Commercial 3D printers are able to create larger-scale and more robust objects. Scientists are already exploring the use of special 3D printers — bioprinters — to make living body parts.
• Laser printer operation


  1. Create bitmap image of page

  2. Apply negative charge to print drum

  3. Use laser to change polarity on drum based on bitmap

  4. Expose drum to positively charged toner

  5. Transfer toner to paper

  6. Fuse toner to paper
• Laser printer


  • Can produce colour printouts
  • Has four different toner cartridges: Cyan, Magenta, Yellow, and Black
  • Each toner is applied in turn to achieve the correct colour print